A Framework for the Derivation of WCET Analyses for Multi-core Processors

Multi-core processors share common hardware resources between several processor cores. As a consequence, the performance of one processor core is influenced by the programs executed on the concurrent cores. We refer to this phenomenon as shared-resource interference. An explicit consideration of all such interference effects is in general combinatorially infeasible. This makes a precise worst-case execution time (WCET) analysis for multi-core processors challenging. In order to reduce the complexity, WCET analyses for multi-core processors coarsely approximate the behavior of the considered applications. However, current approaches are only applicable to rather restricted classes of hardware platforms. We propose a framework for the derivation of WCET analyses for multi-core processors. It relaxes the restricting assumptions that existing approaches are based on. The derivation starts from a WCET analysis that makes maximally pessimistic assumptions about the shared-resource interference. More precise interference bounds for the concrete system are subsequently lifted to the approximation of the analysis. The lifted bounds are finally incorporated in the analysis in order to model the interference in a more precise way.